The mixing of two or more liquid-phase materials or the dispensing of a reagent material on a microchip is accomplished by controlling the electric potentials applied to the various reservoirs to electrokinetically drive the materials housed therein through the channels of the microchip. Heretofore, this process has required external voltage control means such as a power supply employing a voltage divider network, or programmable power supplies. Such external voltage sources are utilized to effect valving and mixing phenomena in the channel manifold of a microfabricated device.
Because of the configurations of the known voltage sources it has been necessary to use a plurality of voltage source leads and corresponding microchip contact points in order to apply the multiple electric potentials. The number of such sources and accompanying hardware to effect electrokinetic phenomena can be quite bulky and require complex architectures to control. This is most evident in highly parallel architectures, especially if each node requires a different applied potential from an external source.
Therefore, a need has arisen for a microchip that is capable of mixing sample material in various proportions and dispensing variable volumes of a sample material in which the fluid material is driven electrokinetically by a single high voltage supply. In this way, excess wires and circuitry needed for a voltage division scheme or the complexity of multiple programmable power supplies can be eliminated and the microchip can be implemented with fewer fluidic reservoirs compared to the known designs.